Current practice in the automotive brake industry uses an elastomeric bushing with a hand-inserted cylindrical polytetrafluoroethylene liner in the slider pin bore of the disc brake caliper as shown in FIGS. 8 and 9 of U.S. Pat. No. 4,228,726. The axial length of the liner is shorter than that of the elastomeric bushing and is designed to fit into a recess in the I.D. of the elastomeric bushing. Such prior art liner does not extend all the way to the outboard end of the elastomeric body and does not have a radially inwardly extending scraper lip. The prior art polytetrafluoroethylene liner is formed from a square of material into a split circular tube. Such liner does not always conform to the inside wall of the elastomeric bushing, making it susceptible to installation damage and sometimes removable from its working position. For example, during assembly, it is common for the polytetrafluoroethylene liner to be pushed out of the elastomeric bushing. Further, such prior art elastomeric bushing includes a pair of radially outwardly extending flanges, defining therebetween an O.D. groove in which the caliper bore is received. The forward or inboard one of the two flanges makes installation of the elastomeric bushing virtually impossible without first folding the bushing, again relying on manual procedures. If the polytetrafluoroethylene liner were placed in the bushing prior to inserting the bushing in the bore, it would probably be impossible to fold the bushing as needed for installation. Further, the known practice does not sufficiently seal against foreign particles entering into the bushing where they can cause the slider pin to bind within the bushing. This causes excessive wear of the brake lining on the inboard disc brake pad. Further, in the current practice, the purchasing, inventory, handling and assembly are relatively expensive since two separate parts are involved.
It is an object of the present invention to provide an improved disc brake assembly and method which overcome the problems in the prior art such as those described above. It is another object of the present invention to provide a disc brake assembly and method which employ a unitary, one-piece, molded tubular bushing seal including a molded tubular elastomeric body having a hydraulically formed tubular polytetrafluoroethylene liner bonded to the I.D. of the elastomeric body and having a polytetrafluoroethylene scraper lip adjacent the inboard end of the bushing seal for scraping dirt and other foreign particles off of the slider pin as the slider pin and bushing seal more relative to each other. It is an object and advantage of the present invention to prevent binding between a disc brake slider pin and the bushing seal of a disc brake caliper thus preventing excessive wear of the lining of the inboard disc brake pad. It is another object and advantage of the present invention to reduce the cost of purchasing, inventory, handling and assembly of a disc brake assembly. It is another object and advantage of the present invention to provide for faster and improved installation of a disc brake assembly without requiring a high degree of manual dexterity.